Crank-operating gear for moving the breech in machine guns



A. H. G. FOKKER. CRANK OPERATINGGEAR FOR MOVING THE BREECH IN MACHINEGUNS.

APPLICATION FILED SEPT. 1. I920- v 1 427 079 Patented Aug. 22, 1922wlfiZ/w UNITED STATES PATENT OFFICE.

ANTHONY HERMAN GERARD FOKKEIR, OF AMSTERDAM, NETHERLANDS.

CRANK-OPERATING GEARFOR MOVING THE BREEGH IN MACHINE GUNS.

Application filed September 1, 1920. Serial No. 407,539.

To all whom itmag concern.-

Be it known that I, ANTHONY HERMAN GERARD FOKKER, a subject of the Queenof the Netherlands, residing at Amsterdam, Netherlands, have inventedcertain new and useful Im rovements in Crank-O erating Gear for Klovingthe Breech in achine Guns (for which I have filed a plication inGermany, No. 310,067, filed Fe 12, 1918), of which the following is aspecification.

The type of machine gun in which the breech block, the movement of whichplaces a cartridge in position and operates the firing pin, is given areciprocating movement by mechanical means, such as a rotating crank,instead of being returned to the cooked position by the recoil of theexplosion in the gun, is well known. In the usual form of constructionin such a gun, the extreme forward position of the crank brings thebreech block to the point where it holds the cartridge in position andthe shot is fired.

The object of the present invention is to provide a means of bringingthe breech block into its forward position before the operating crankhas reached the end of its throw in order to utilize the remainder ofthat throw for operating a device for locking the breech block inposition before the shot is fired. This means of locking forms thesubject of my copending apglication for Letters Patent of the Unitedtates, Serial No. 407,540, filed September 1, 1920.

The accompanying drawing illustrates the construction of the n mechanismwhich forms the subject of this invention.

In said drawing Figs. 1 and 2 respectively show vertical and horizontalsections through the gun mechanism.

Fig. 3 is a cross section through A-B Fig. 1.

The operatin crank A is connected to the breech block E by means of aconnecting rod, which. however, consists of two telescoping parts and C,one of which slides axially inside the other, the two parts beingextended as far as allowed by the crank A and the breech block E bymeans of a spring D.

When the crank A has completed part of its forward throw as indicated bythe center line F, the breech block is forced against the abutment G andholds the cartridge carrier- L in place. In continuing its rotation fromthe position shown from the center line F to its furthest forward point(the position in WhlCh 1t 1s shown in the diagram), the crank A forcesthe two parts of the connecting rod together, thus compressing thespring During this time the breech block E remains stationary while themovement of the crank is utilized to move the lockin levers K into theposition in which they look the breech block in the manner described inmy copend ng appl cation hereinbefore identlfied, Serial No. 407,540.When this has been efi'ected the shot is fired. The continued rotationof the crank A first unlocks the breech block by moving the lockinglevers K, duringwhich time the breech block remains statlonary while thetwo parts of the connectmgrod slide outwards, decompressng the spring D.When the connecting rod 1s fully extended the further rotation of thecrank draws the breech block away from the abutment and the cycle ofoperations is repeated by the means described. The rotation of theoperating crank remains continuous and uniform throughout the cycle ofoperations.

Having now particularly described and ascertained the nature of my saidinvention and in what manner the same is to be performed, I declare thatwhat I claim is 2-- 1. In a breech block mechanism for machine guns, arotating crank, a connectin rod between the crank and the breech block,

divided into two parts in a manner allowing the said connecting rod tochange in length during the transmission of the movement of the crank tothe breech block, whereby the movement of the breech block is less thanthe total throw of the crank.

2. In a breech block mechanism for machine guns, a rotating crank, aconnectin rod connecting the operating crank with the breech block,divided into two parts, one sliding axially within the other, and aspring holding the two parts extended as far as allowed by the relativepositions of the crank and the breech block.

In testimony whereof I afiix my signature in presence of two witnesses.

ANTHONY HERMAN GERARD FOKKER. Witnesses:

